Image control device and method of printing



IMAGE CONTROL DEVICE AND METHOD OF PRINTING Filed 001;. 31, 1957 INVENTOR.

United States Patent Ofifice 3,056,136 Patented Sept. 25, 1962 3,056,136 IMAGE CONTROL DEVICE AND METHOD OF PRINTING Jack E. Macgrifi, 9023 W. Outer Drive, Detroit, Mich. Filed Oct. 31, 1957, Ser. No. 693,690 6 Claims. (Cl. TAG-74) This is a continuation in part of my (so-pending patent application Serial #410,090, filed February 15, 1954, which is now abandoned.

This invention relates to an image control device, and method of printing, and more particularly to a sensitive image control device responsive to variations in light intensity focused from an image and in its responses to such variations adapted to control the flow of electrons through an enclosed smoke pigment for deposition of ionized pigment particles upon a moving image web.

It is the object of the present invention to provide a novel method of printing, utilizing a sensitive image control mechanism.

It is the further object of the present invention to provide a novel image control device for transmitting a high voltage current through a confined smoke pigment for impinging upon a moving web in a permanent manner ionized particles of pigment with the amount of deposi tion controlled by variations in light intensity focused from the image to be printed upon the photosensitive portion of the image control device.

It is the still further object of this invention to provide a novel method of printing by said image control device directly upon an electro-sensitive web.

These and other objects will be seen from the following specification and claims, in conjunction with the appended drawing, in which:

FIG. 1 is a fragmentary diagrammatic partially sectioned view of the printing apparatus embodying the present invention.

FIG. 2 is a fragmentary diagrammatic illustration of a slightly different form of printing apparatus.

FIG. 3 is a front elevational View of the light shield used.

FIG. 4 is a side elevational view of the stationary electrode blade employed.

FIG. 5 is a fragmentary bottom plan view thereof.

FIG. 6 is a side elevational view of the image control device shown in FIG. 1, upon an enlarged scale.

FIG. 7 is a fragmentary plan view thereof; and

FIG. 8 is a diagrammatic illustration of a slightly different type of image source in conjunction with the image control device.

It will be understood that the above drawing illustrates merely a preferred embodiment of the invention, and that other embodiments are contemplated within the scope of the claims hereafter set forth.

Referring to the drawing, the present printing apparatus has an electronic image control device generally designated at 35, and as shown in FIGS. 6 and 7 includes a non-electrically conductive insulating base 1, which may be glass, plastic or any non-electric conducting material; and mounted thereon are a plurality of horizontally disposed parallel spaced conductors 2 arranged in a row. These are .001 to .005 inch wide and spaced apart 100 to 500 per lineal inch. These are secured to the base in insulated spaced relation to each other. A photo-sensitive layer 4 is mounted over conductors 2 and in contact therewith, said photo-sensitive film being made from selenium, for example, which has a relatively high electrical resistance and has the characteristic of changing its electrical resistance when exposed to light, and therefore is photoconductive.

The image control device 35 of FIG. 1 is shown in elevation on an enlarged scale in FIG. 6 whereas FIG. 7 is a fragmentary plan view of the structure of FIG. 6.

Mounted upon the photo-sensitive layer 4, and in contact therewith, is a transparent electrode layer 5, which is adapted for connection by the wire lead 30 to the high voltage line 29 from a suitable source of direct current. Mounted over the transparent electrode layer 5 and in longitudinal alignment with insulating cover 3 is a transparent protective covering layer 6 to complete the image control device 35.

The transparent electrode layer 5 may be a thin evaporated transparent film of an electrically conductive metal such as platinum, silver, or stannous chloride, for example. Transparent electrode layers are well-known. By transparent electrode layer is meant a layer of electrode material that is transparent to the radiation of portions of the electro magnetic spectrum extending from the infrared to the ultra-violet. This electrode layer must be transparent or transluscent to light so that variations in light intensity of the source such as at 7' FIG. 1 will control the electric conductivity of the photosensitive layer 4 in FIG. 6.

I refer specifically to the book, Photoelectricity and Its Application, by V. K. Zworykin and E. G. Ramberg, published by John Wiley and Sons, with first copyright in 1930 and edition referred to by this inventor as that printed in July 1950. This book is a standard text commonly used in the art. 011 page the author describes preparation not only of a transparent electrode layer but of a transparent photo-surface! Such a transparent electrode layer is currently used in the commercially available miniature phototube type IP42 manufactured by Radio Corporation of America (RCA). Such a transparent electrode layer is also used under transparent photo-cathodes in all image tubes. Such a tube is described on page of the same book, and the transparent electrode layer is also described at the bottom of page 155 which is deposited as a thin, transparent metallic film serving as an anode. On page 198 of the same book, line 3, Langes immediate contribution was the employment of a transparent contact electrode, usually gold or silver, sputtered on the cuprous oxide surface. On page 199 of the same book, line 8, Front Wall cells may be produced by chemically or electrolytically reducing the surface layer of the cuprous oxide to form the (copper) top electrode or by sputtering the top electrode material (gold, silver, platinum, or nickel) onto the cleaned cuprous oxide surface in a reducing atmosphere. A drawing of a transparent electrode layer is shown on page 202 of the same book, and line 20 of the same page states, The top electrode may be applied by evaporation, sputtering or spraying; Selenium photo-conductive cells with such a transparent electrode layer are manufactured by the International Rectifier Corporation (IRC) of El Segundo, California.

In order to form or print images with the present device, the image 7 sought to be reproduced is affixed or otherwise secured to the outer surface or rotatable drum 8, which has a central axis of rotation 22.

The light 9 upon the exterior of drum 8 illuminates a strip of the image 7', and this illuminated strip or the image 19 thereof, is projected by the lens 10 through the horizontally elongated slot 28 of light shield 18 and thence to the direction changing mirror 11.

The image 7 is thus projected through transparent cover 6, through the transparent electrode layer 5 and onto the photo-sensitive layer 4 for regulating the internal resistance thereof in turn controlling the quantity and flow of electrons through the respective conductors 2 from the current lead 29 which is connected to electrode layer 5. It will be understood that the mirror could be eliminated where the image line 7 is so arranged as to be focused directly upon the photo-sensitive layer, such as the image line 36, illustrated in P16. 2.

A moving web of paper or other image base 12 extends around and passes over the revolving drum 13, the axis of rotation of drum 13 being parallel to the axis of rotation of drum 8.

As shown in FIG. 1, in the event that a transparent image 7 is employed upon the drum 8, the light source 9 may be positioned upon the interior of drum 8, rather than the exteriorly arranged light 9, which is adapted for use in conjunction with opaque images.

The outer ends of conductors 2 extend outwardly beyond the end of the image control device 35, and lie in a plane parallel to drum axis 21, the same ends of said conductors being spaced a short distance, approximately .010 to .100 inch from moving web 12. There is provided a stationary electrode blade or comb 14, which has a horizontally disposed thin electron receiving edge 23, which is preferably formed with a series of longitudinally spaced comb-like projections 24, as indicated in FIG. 5, said blade being connected to the return wire lead 31 for completing the high voltage circuit. Said electrode blade 14 of FIG. 1 is shown on an enlarged scale in 'FIG. 4 and FIG. is a fragmentary bottom plan view thereof showing comb-like projections 24.

There is provided a suitable housing 26 through which passes a smoke-pigment 15 of uniform density, there being connected to said housing through the conduit 25, smoke pigment generator 16, whereby the particles of smoke pigment are forced between the ends of conductors 2 and the image web 12 by the blower 17 or other equivalent device. Though the upper portion of the housing 26 is broken away, for illustration, it is contemplated that the same be connected to the conduit 25, so that said smoke-pigment may be recirculated continuously. The housing 26 includes the opposed out- Wardly projecting arcuate formations 27, which are spaced outwardly from portions of the moving web 12, as indicated in FIG. 1.

The light shield 18 limits the light 19 falling on the photosensitive surface 4 to the illuminated image strip 7'. Said light shield 18 is shown on an enlarged scale in FIG. 3 and has formed therethrough the elongated slot 28.

In operation, the drum 13 is suitably connected with a driving means, also connected with drum 8, so that both drums are synchronized for movement in unison. The variations in light intensity from the image lines 7 of image 7 falling on the photo-sensitive coating 4 change the electrical resistance of portions of the coating thereby regulating the flow and quantity of electrons through each of the respective conductors 2.

The high voltage is transmitted from the transparent conducting electrode 5 to the stationary electrode 14 arranged upon the interior of drum 13. In operation, as the electrical resistance of portions of the photosensitive coating 4 drop or vary due to the application thereonto of light images 7' with portions thereof of varying light intensity, electrons are permitted to flow from the ends of conductors 2 in varying quantities through the smoke 15 and to the electrode 14.

As the electrons pass through the smoke-pigment, particles of the ionized pigment are carried by said electrons to the image web 12 and impinge upon said web and into the surface thereof in a permanent manner, thereby reproducing the particular image line 7 focused through the lens 10. Consequently, as the image 7 is revolved with drum 8, it is reproduced on the moving web 12 instantaneously by a continuous deposition upon said web from each of conductors 2.

It is contemplated that a constant density of smokepigment be maintained Within housing 26 at the space 4 between the ends of conductors 2 and the web 12 of image receiving material.

Smoke pigment particles or ions may carry an electro-static or electro-magnetic charge to assist the image deposition upon the web 12, which charge is pr vided for in a standard and conventional manner, such as by establishing an electro-static or e1ectro-magnetic field through which the smoke particles pass.

A slightly different method of printing is illustrated in FIG. 2, wherein the present image control device 35 is also employed and the image line 36 is transmitted directly through the transparent protective cover 6, through the transparent electrode layer 5 and onto the photosensitive layer 4, in the same manner above described in connection with FIG. 1.

There is also provided a drum 33 fragmentarily shown, having an axis of rotation 34 and around which passes the electro-sensitive paper 32 or other material. There is also provided the electrode 14 for receiving the flow of electrons from the ends of conductors 2 in the manner above described, except that here there is no deposition of smoke-pigment, but on the other hand the pigment is in the electro-sensitive paper. This means that the ends of the conductors 2 must be substantially in direct contact with the web 32. The high voltage current is delivered through the lead wire '37 to the electrode layer 5 and the flow of electrons, as regulated by said image control device pass through the sharp edge 23 of electrode 14 completing the electrical circuit through the lead wire 38.

FIG. 2 thus illustrates a slightly different form of printing apparatus, which nevertheless utilizes the present image control device.

Referring to FIG. 8, there is shown a diagrammatic illustration of a vibrating type of image source used in conjunction with the image control device 35, hereinbefore described.

There is provided a concave or arcuate plate 38' of constant radius which has upon its interior surface the image sought to be printed under the control of image control device 35, which image is generally designated at 39.

Sources of light 40 illuminate the image and the pivotal mirror 44 is adapted to pick up portions of said image as it is rotated at pivot point 45. In other words, the reflected image will encompass the entire scope of the image between the image lines 41, 42 and 43, shown in dash lines in the drawing.

The mirror 44 has a support which is pivoted at 45 and said support has an arm 46 and a contactor 47, at its free end, engageable with the surface of the cam 48 which rotates about axis 49 as indicated by the arrow.

The contactor is maintained in continuous engagement with said cam by the coiled spring 50, so that upon rotation of said cam said mirror will be swung through the are shown. The reflected image from mirror 44 passes through the lens 51 as at 52 and through the apertured shield 53 similar to shield 18 of FIG. 3. The direction changing mirror 54 receives the image and focuses it upon the photo-sensitive layer 4 of the image control device as indicated in FIG. 6.

The purpose of FIG. 8 is to illustrate that instead of mounting the image upon a moving source, such as drum 8, FIG. 1, the image 39 may be stationary and the mirror 44 movably mounted reciprocally, so as to progressively sweep the surface of said image.

The insulating cover 36 of the image control device 35 may be constructed of glass or of a plastic substance and is transparent or translucent. The forward portion 3 of the cover beyond the transparent electrode layer 5 and the photosensitive layer '4 may be opaque, if desired.

Having described my invention, reference should now be had to the following claims.

I claim:

1. An electron emission control device comprising an electrically non-conductive insulating support, a row of parallel conductors retained in precise spaced geometric insulated relation on said support, with one end of each conductor extending beyond and terminating adjacent one edge of said support, a layer of photoconductive insulating material mounted across and in contact with a portion of each of said conductors remote from said one end, an optically transparent electrode layer juxtaposed upon and in contact with the side of said photoconductive layer remote from said conductors, said transparent electrode connected to a source of electric potential, an optically transparent and electrically non-conductive insulating cover extending over said transparent electrode and over said conductors with said cover terminating at the edges of said non-conductive insulating support, so that the entire device is enclosed except the said one end of said conductors and the connection from the transparent electrode to the source of electrical potential.

2. The device of claim 1, an accelerating electrode spaced from and parallel to the said one end of the conductors, and a source of electric potential connected between said transparent electrode layer and said accelerating electrode for establishing an electrical field between the ends of said parallel conductors and said accelerating electrode, with the strength of said field at any geometric location and instant determined by the electrical resistance of said photoconductive layer intermediate said transparent electrode and said corresponding parallel conductor in contact therewith.

3. The device of claim 2, with the said one end of said conductors adapted to emit electrons, and a movable receiving surface movably positioned between and spaced from the emission ends of said conductors and said accelerating electrode, there being a rectilinear strip of light from a portion of a movable image displayed upon the photoconductive layer, with the intensity of said light at any particular geometric location on said photoconductive layer determining the electrical resistance of said layer intermediate said transparent electrode and the corresponding insulated parallel emission conductor, with the quantity of electrons emitted from the emission ends of said parallel conductors determined by the electrical resistance of the photoconductive layer between and in contact with said conductor and said transparent electrode, with the electrons emitted from the emission ends of said conductors in the direction of said accelerating electrode imposing an electrostatic charge on the receiving surface opposite therefrom, with the movement of the receiving surface and the portion of image displayed by rectilinear strip on the photoconductive layer synchronized to form electrostatic charges on the movable surface in a predetermined pattern.

4. The device of claim 3, and a housing to confine finely divided particles of pigment in cloud form in proximity to the space between the emission ends of said parallel conductors and said movable receiving surface, so that finely divided particles of pigment are maintained in a constant density cloud with particles of pigment deposited on said surface by action of the electrical field generated between said emission of said conductors and the accelerating electrode, with the quantity of pigment thusly deposited controlled by the intensity of said field at any particular geometric location or instant.

5. A method of forming electrostatic images compris ing movably positioning a receiving surface in spaced relation from an electron emission control device that emits variable amounts of electrons in a rectilinear line in response to a rectilinear strip of variable light displayed upon it, with the amount of electrons emitted at any geometric location along said rectilinear line variable from the quantity emitted from any other geometric location, at any selected instant, evenly illuminating an original image with light, displaying a rectilinear strip of light from the original image upon said device, positioning an accelerating electrode on the opposite side of said movable receiving surface, connecting a source of electric potential between said device and said accelerating electrode so that electrons emitted from said device will travel in the direction of said accelerating electrode and impose an electrostatic charge on said receiving surface, synchronizing the movement of the entire original image across the rectilinear strip displayed on the electron emission control device with the movement of said movable surface and thereby generating on said movable surface an electrostatic image, controlling the intensity of said electrostatic image at any particular geometric location on said surface by the intenstiy of light displayed from the corresponding geometric location on the original image.

6. A method of forming pigmented images comprising movably positioning a movable receiving surface in spaced relation from an electron emission control device that emits variable amounts of electrons in a rectilinear line in response to a rectilinear strip of variable light displayed upon it, evenly illuminating an original image with light, displaying a rectilinear strip of light from the original image upon said device, positioning an accelerating electrode on the opposite side of said movable receiving surface, connecting a source of electric potential between said device and said accelerating electrode so that electrons emitted from said device will travel in the direction of said accelerating electrode, maintaining a cloud of finely divided particles of pigment in constant density in proximity to the space between said electron emission control device and said receiving surface, depositing particles of pigment on said surface by action of the electric fields generated by said electron emission control device, with the quantity of pigment deposited determined by the quantity of electrons emitted from said device, synchronizing the movement of the entire original image across the rectilinear strip displayed on the electron emission control device with the movement of said movable surface and thereby generating on said movable surface a pigmented image, and controlling the deposition of pig ment at any particular geometric location on said surface by the intensity of light displayed from the corresponding geometric location on the original image.

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